In doubles, this Chimecho moveset is vulnerable to double targeting because it doesn't have protect.
In singles, Chimecho has bad offensive typing and coverage moves, which makes it easy to check for Samurott, Ceruledge, and just about every steel Pokemon. Mega Chimecho also prevents you from mega evolving a better Pokemon. If you want a defensive Pokemon that's good at boosting, you should use Aegislash or Kingambit instead.
source
source
source