There are lots of teams that are interested in Nash, but he's not all that interested in leaving. He's certainly not demanding a trade (the Suns offered to trade him to a contender for the twilight of his career and he declined).
The biggest stories of this year will be in the destinations of Dwight Howard, CP3, Nene, and perhaps D-Will. Lots of crazy possibilities.
The Heat will likely end up with Dalembert (unless Nene was serious when he said he doesn't care about money at all). This will be a substantial upgrade at Center and with Haslem back as well it's hard to see any team finishing with a better record in the regular season. Perhaps a healthy Bulls squad can challenge them, but nobody else seems likely. If the Heat end up with Nene it's pretty much game over for the league barring catastrophic injury.
I hope the Clippers are good. They're reportedly one of two teams CP3 wants to play for and unlike the Knicks, the Clips have pieces to trade and cap room. Even without upgrading their roster, Mo Williams/Gordon/?/Griffin/Kaman is pretty good and if they're healthy they could win 35-40 games in this shortened season (they were pretty good for the second half of last season).
I fully expect the Knicks to be underwhelming unless they can manage to steal CP3 or Dwight Howard somehow, but they have nothing of trade value. Best case scenario for them one of the superstars holds out until next season and the Knicks can pick 'em up. This season is a lost cause, though.
Which team will be the worst? The Bobcats make a compelling argument for this one, most non-Charlotte fans probably can't even name 2 Bobcats. The Cavs are still going to be bottom feeders even if Irving and Thompson live up to expectations early on, The Wolves may still suck (IMO Rubio is one of the most incredibly overrated players ever), the Raptors won't have Valuncianas and their roster is still lamentable, if the Hornets trade Chris Paul early they'll probably be one of the worst teams in the league, and the Pistons don't really have much going for them other than Greg Monroe. Also the Kings and Wizards are still bad, sorry.
Which teams have a legit shot of winning this year? The Heat and the Bulls are both in strong positions to take the title (and yes, the Bulls DEFINITELY need to address their SG woes), the Thunder will finally be in a position to be the best team in the Western Conference. Tyson Chandler has all but promised he won't be a Maverick next year, condemning them to a likely second round exit. The Lakers are in the mix but it's hard to really predict with Bynum's health, Mike Brown as head couch, and a roster that won't be improved any over last season (unless they swing a big trade).
The Celtics are probably just about done. That team won't be able to handle 3 games in 3 nights, their bench is looking pretty shallow, they don't have cap space, they don't have anyone at Center except Jermaine O'Neal's corpse, and KG is nearing the end.
The Magic are about to enter a horrible rebuilding mode and probably won't even take one last shot at a championship (think Nuggets from last year). If you're a Magic fan, just hope you get a good deal for Dwight.
The Hawks will be the same team they always are.
The Knicks may win a round in the playoffs this year but don't have a reasonable chance of winning a 7 game series against the Bulls or Heat.
The Spurs have an outside shot of getting deep in the playoffs but their window is nearly shut. Duncan won't be able to put in even 30 minutes a night and Ginobli is getting old, too.
The Grizzlies may lose Marc Gasol this free agency period (though probably not). If they do, they're not really anything anymore. If they don't, I still don't expect them to do any better than reaching the second round in the West if they're lucky.
The Blazers could be great if Oden finally magically doesn't have any problems, but nobody is expecting that (I also find it unlikely that any other team will offer him a contract greater than the QO that Portland has already offered him). Assuming he's still a 50 year old man with bones of glass, Portland is looking at a likely first round exit, Aldridge and Wallace can only carry them so far.
If the Warriors can pick up one of the Centers on the market they could break into the playoff picture but they still wouldn't be able to get deep.
The Suns are done and if you're a Suns fan, I'm sorry. Because not only is your team not going to win, but they're also delaying their rebuilding mode. Nothing is worse than having a middling team. They should trade Nash for a pick and a prospect if they can.
The Nuggets entire team is playing in China right now or leaving to free agency. I have no idea what they'll look like this season, but expect them to be handing out bad contracts at the last second because they're like 20-30 million short of the minimum salary and they only have seven or eight players on contract. Too bad, after their strong finish last season.