Nivens rhymes with:
bivens, divens, enlivens, ivens, scrivens, avon's, beethoven's, bevans, bevens, bivens, blevens, calvin's, craven's, cravens, devens, divens, donovan's, donvan's, eleven's, elevens, enlivens, evans, evans', evens, givens, havens, heaven's, heavens, hillhaven's, ivens, leavens, levens, maven's, mavens, nonwovens, ovens, ravens, sarajevan's, sarajevans, scrivens, seven's, sevens, slavens, stephen's, stephens, steven's, stevens, stevens', sullivan's, sullivans
Nivens sounds like:
nabbing, napping, nevin's, nevins, nifong, nipping, nonbank, nonpaying, nonwovens, numbing, numbness, nupeng, nvhomes, nymphomaniac, nymphomaniacs