Oversizing rhymes with:
sizing, upsizing, advising, arising, chastising, comprising, decriminalizing, despising, devising, disguising, revising, rising, sensationalizing, sizing, surprising, unsurprising, uprising, upsizing
Oversizing sounds like:
oppressing, oppressions, overarching, overcomes, overcoming, overcooking, overreaching, overseeing, overusing, overworking