Kenneth G. Wilson (1923). The Columbia Guide to Standard American English. 1993.
nicely (adv., adj.)
As adverb nicely is Standard, meaning well, satisfactorily, acceptably, appropriately: She was nicely dressed. He thanked his grandmother nicely. As adjective in predicate adjective position, nicely is at best dialectal: She looks nicely. Use nice instead. But compare FEEL BAD.