Stephen Colbert is declaring victory in his feud with Donald Trump, saying it's pretty rich of the prez to bring up ratings ... when his approval numbers are in the toilet.

Colbert was more than happy to respond to Trump calling him a "no-talent guy." In his Thursday night monologue, he said, "I've been trying for a year to get you to say my name ... I won."

The host also addressed Trump saying he has a "filthy mouth" -- "I do occasionally use adult language, and I do it in public instead of the privacy of an 'Access Hollywood' bus." Ya walked right into that one, Mr. Commander-in-Chief.

Check out the rest of the skewering ... which covered ratings, Nixon and Alfred E. Neuman. Hysterical.