Nighthawk rhymes with:
blackhawk, echohawk, goshawk, mohawk, seahawk, skyhawk, tomahawk, airlock, blackhawk, boardwalk, cornstalk, echohawk, gamecock, goshawk, honestok, jaywalk, kowalke, marschalk, mohawk, norwalk, poppycock, seahawk, sidewalk, skyhawk, sleepwalk, smalltalk, tomahawk, witbrock
Nighthawk sounds like:
nacogdoches, nasdaq, nasdaq's, nast's, nastasi, naugatuck, necessitates, necessities, neckties, negates, negotiates, nest-egg, nests, newscasts, newsday's, next's, niceties, night's, nighthawks, nights, nights', nonjets, nonstick, nugget's, nuggets