Shadow Sneasler

Despite the Shadow boost, Sneasler still can't quite make it to the title of "good". This is primarily due to the fact that it's it still doesn't have a Poison moveset, and is primarily competing as a Fighting Type, which is a meta that it cannot compete in.

Best PvE Offensive Moveset

• Rock Smash pairs well with Close Combat to fulfill a Fighting-type role.
• Poison Jab is a good Poison-type move with STAB, but lacks synergy with the available Charge Moves.
• X-Scissor or Aerial Ace could be chosen to attack Grass-types, but other Pokemon are better for this. 

Best PvE Defensive Moveset

• Rock Smash is generally the stronger option for defense with its respectable base power and STAB. 
• Poison Jab is a decent STAB alternative. 
• Shadow Claw has a very high chance to not be resisted by attackers, but is weaker. 
• Aerial Ace or X-Scissor are the way to go for a Charged Move.

Poison Jab benefits from STAB to deal respectable damage, but its coverage is rather limited. Shadow Claw can be chosen for its typing which is largely unresisted by most Pokemon. 

Close Combat is always recommended for its powerful STAB coverage, despite the harsh self-debuff. X-Scissor costs the least amount of energy in the game, allowing it to be spammed frequently and bait shields. Aerial Ace is not recommended due to its unimpressive stats, unless Flying-type coverage is needed.