Noivern

Notable for its pre-evolution Noibat being the rarest Pokemon during the Gen 6 Kalos debut, Noivern unfortunately doesn't have any use in the meta to make up for the difficulty in obtaining it. Inferior stats and an awkward moveset leaves this bat as a dex filler at best. 

Best PvE Offensive Moveset

• Air Slash benefits from STAB and fulfills a Flying-type role.
• Bite doesn't suit Noivern.
• Draco Meteor is the most powerful move available, but isn't very synergistic with Noivern's fast moves.
• Hurricane benefits from STAB and synergizes with Noivern's fast move easily. 
• Psychic actually performs better than Hurricane when Super Effective, despite lacking STAB, but falls behind otherwise.
• Heat Wave is useless. 
• Boomburts* is pretty underwhelming.

Best PvE Defensive Moveset

• Air Slash is superior on defense due to its significantly stronger base power.
• Bite is quite weak on defense.
• Psychic is the only 2-bar move available, and is relatively unresisted against Noivern's counters.
• Hurricane has the earliest damage window, but Noivern might faint before it gets to use it. 
• Heat Wave, Draco Meteor, and Boomburts* are all very poor for defense. 

Air Slash benefits from STAB and sports average energy generation. Bite has strong base damage, but lacks STAB and has very poor energy gains. 

Psychic is the cheapest charge move energy-wise, and recommended solely for this reason. Draco Meteor and Hurricane tie for the same energy cost and both get STAB; the former is incredibly powerful but risky with its self-debuff, while the latter is less risk and less rewarding. Heat Wave is very bad for PvP.