Yeah Tangela is a great mon. Quite a few people have used it, and while it isn't as good as last gen it still puts in workTangela @ Eviolite
Ability: Regenerator
EVs: 252 HP / 252 Def
Bold Nature
- Leech Seed/Toxic
- Stun Spore
- Protect
- Giga Drain/Synthesis
Why it isn't a Sunkern: I don't think i've ever seen Tangela used in the NU aside from me, but Tangela has an amazing bulk with her 110 base Def and with eviolite and recovery, and can absolutelly stall alot of pokemons in the tier and cripple them. Even without spending EVs in Def, she has 399 Def and can be made into dedicated physical wall that can outlast surprisingly a lot of pokemons in the tier reaching an astoundishing 541 Def, and get away with it back to close to full health with refilling from Regenerator ability. With stun spore/leech seed or toxic, you are almost guaranteed to cripple any incoming counter and safely switch to it's check.
Another set worth mentioning, is without Eviolite but with a Scope Lens to replace Stun Spore with Sleep powder while keeping good 361 def, for which she might as well simply use leftovers and function with a different kind of recovery, but in my opinion Leftovers is inferior to other sets because Tangela already has amazing recovery capacity.
Besides being NFE (actually LC Uber), Tangela is not really item dependant and usually can still partially perform well after having it's eviolite knocked off.
A much better set for it is as follows though:
Tangela @ Eviolite
Ability: Regenerator
EVs: 252 HP / 252 Def
Bold Nature
- Leech Seed
- Giga Drain
- Synthesis
- Hidden Power Fire / Stun Spore / Sleep Powder / Toxic
Leech seed is necessary as coupled with regen it allows tangela to seed switchins then easily back out into a check
Synthesis is also necessary to keep tangela around, as you'll find yourself worn down without it, especially if you've lost your eviolite
The final slot has an array of options, HP Fire is nice to avoid being walled by grass types, stun spore for crippling switchins such as typhlosion, magmortar, archeops (basically anything that likes its speed) sleep for sleeping the swithins and toxic for switches and stalling alongside synthesis.
I'd recommend just running HP fire though because the other options are all usually used on the switch, when you'll most likely be better off leech seeding the switchin or switching out yourself