[Pros]
<ul>
<li>Great physical bulk allows it to counter an array of physical attackers, with Excadrill being the most important.</li>
<li>Decent Attack stat Its Attack stat is decent.</li> (you can make whatever change here you want as long as this is a complete sentence)
<li>Ability that makes him Its ability makes it immune to bomb-based and ball-based attacks, such as Shadow Ball and Aura Sphere.</li> (same for the rest of these that I'm turning into complete sentences)
<li>Access It has access to Spikes.</li>
<li>Reliable It has a reliable recovery move.</li>
</ul>
[Cons]
<ul>
<li>Low Its Special Defense is low.</li>
<li>Low Its Speed stat is low.</li>
<li>Serious It has a serious weaknesses to Flying- and Fire-type attacks.</li>
<li>Poor It has a poor movepool.</li>
<li>Its recovery gets weakened against sand teams.</li>
</ul>
[Set Recommendations]
<p>Chesnaught @ Leftovers<br />
Ability: Bulletproof<br />
EVs: 252 HP / 252 Def / 4 Spe <br />
Impish Nature (+Def, -SpA)<br />
- Spikes<br />
- Synthesis<br />
- Hammer Arm<br />
- Seed Bomb</p>
<p>Since Because Defog now clean all the fields from entry hazards, Spikes aren't the best bet anymore but they still are somewhat useful. Chesnaught is different from Ferrothorn and Roserade. It has Fighting STAB, Ground resistance, Dark resistance (add comma) and Fighting neutrality, so he it can switch in for example against Choice Band Tyranitar or and Excadrill, Shell Smash Barbaracle, Pangoro (add comma) and Tytantrum Tyrantrum, all Pokemon that Ferrothorn and Roserade (the next sentence (which I removed) is very redundant, but if there's a better way to work them together, feel free to do so) can't deal with. Unlike Ferrothorn and Roserade, it can beat Tyranitar and Excadrill, and has a solid Fighting STAB. Hammer Arm is the main STAB move that provides more power possible solid power, Synthesis is the main recovery move supplies recovery, and Seed Bomb helps Chesnaught against Water- and Ground-type Pokemon.</p>
<p>The best way to use this set is to eliminate Defog users such as Crobat, which can OHKO Chenaught Chesnaught with its STAB Brave Bird. Rotom-W can switch in against Crobat and Talonflame, forcing them to switch out, so it can use Volt Switch in order to gain momentum since as it's slower. Also, Zapdos can screw over Crobat with its Electric STAB. Magic Bouncer Bounce users such as Xatu or and Mega Absol are scared by Zapdos / Rotom, Mega Lucario, and Mega Gengar. Also, Chesnaught can check and scare a couple of physical attackers (add comma) such as Excadrill, Tyranitar, Tyrantrum, Pangoro, and Barbaracle, and set up Spikes. Chesnaught also serve as an answer to late-game sweepers such as Lucario thanks to Synthesis, which increases its longevity in combination with its great Defense. Another good partner for Chesnaught is Magnezone, which counters Crobat, (remove comma) and traps and KOes Scizor, Skarmory and Forretress, Pokemon that are problematic for Chesnaught. Also, a spinblocker like Mega Gengar is a fantastic partner of for Chesnaught in order to keep entry hazards up against Starmie and Tentacruel, as it can trap and KO both of these spinners.</p>
[Checks and Counters]
<p>Crobat is the best counter. Access to Defog just screws this thing easy, and a x4 4x super effective STAB attack will put Chesnaught out of commission with ease. It can't do much to Crobat in return either.</p>
<p>Flying-type Pokemon such as Talonflame, Hawlucha, Skarmory (add comma) and Xatu are Chesnaught's bane. The former first has Gale Wings have granting priority to its Flying-type moves, so it can OHKO Chesnaught (add comma) putting an end to its chances to set up Spikes or boost with Bulk Up / Swords Dance (I'm not seeing how Gale Wings is relevant here; Chesnaught isn't using priority, and Talonflame is way faster than it naturally anyway; unless I'm missing something, rework this sentence so it doesn't say Talonflame can OHKO because of Gale Wings). Skarmory walls Chesnaught, (remove comma) and can proceed to OHKO it with Brave Bird, Hawlucha can OHKO Chesnaught with Acrobatics, Xatu counters the defensive set reflects Chesnaught's Spikes with Magic Bounce, so Chesnaught have to switch before taking and forces it to switch out to avoid taking a Psychic.</p>
<p> (this is separate from Flying-types) Grass / Poison type Pokemon can freely switch in to take Seed Bomb or Brick Break and Hammer Arm, forcing it Chesnaught to switch. </p>
<p>Chandelure can easily tease Chesnaught. Even if it is behind a Substitute, with Chandelure's ability, Infiltrator, it can attack Chesnaught through the Substitute and OHKO with Flamethrower.</p> (why is hitting through Substitute relevant when there is no mention of Substitute in the set recommendations? Also, some mention should probably be made of how Chandelure is also immune or resistant to Chesnaught's STABs like Trevenant and Gourgeist are)
<p>Trevenant and Gourgeist are solid counters to Chesnaught. Due to their Ghost / Grass typing, they are immune to its Fighting-type STAB and resist its Grass-type attacks.</p>
<p>Aegislash can switch in easily and set up on Chesnaught with Swords Dance, forcing it to switch out.</p>
<p>Toxicroak can seriously damage Chesnaught with a Swords Dance-boosted Poison Jab.</p>
<p> Dragonite and Salamence can easily switch in and set up on Chesnaught and kill it with Fire Punch, Fire Blast (add comma) or Outrage.</p>
<p> Due to Chesnaught's lack of Speed and Special Defense, it can be easily killed by faster and many powerful faster Pokemon, (remove comma) and must rely on hazard or Pokemon support from its teammates in order to get KOs or setup opportunities.</p>