Nebulous rhymes with:
fabulous, calculus, fabulous, meticulous, miraculous, populace, populous, ridiculous, romulus, scrupulous, stimulus, tremulous, unscrupulous
Nebulous sounds like:
nablus, naples, napoles, neopolis, nepalese, nevels, nevills, nevils, nibbles, niblack, niblock, nipples, noble's, nobles, noblesse, nonpluss, nonpublic, novel's, novell's, novellus, novels