D&D 5E Question about Monster Actions

[SilverBulletKY]

Do all actions listed for the monsters get as many uses as you want each encounter? My group just fought a Nothic and I only used the Rotting Gaze once as it did around 13 damage in one hit to the sorcerer. It felt as if it was a action that would require a rest to use again, but nothing is written for this. If I could just have it stand there and cast Rotting Gaze all fight, it would be a quick battle with 3d6 damage on a failed roll to a level 2 party.

 

[Mouseferatu]

Powers/attacks that are restricted in use are called out as such; for example "3/day" or "recharge 5-6" or "wolf form only."

If something is not otherwise noted as being limited, then yes, it can be used every round. In the nothic's case, remember that 30 feet isn't that far (most characters can cover that in a single move) and it only effects one target at a time. So yeah, for a round or two it's pretty nasty, if PCs have been failing saves, but after that the big guns should be able to target it if they haven't already.