Chauncey Welliver, another American, is the holder of the rival New Zealand National Boxing Federation heavyweight title but there is no chance he will fight Williams any time soon because of the animosity between the two boxing associations.
Nasser said he felt under no pressure to agree to any fight against Shane Cameron or Monte Barrett in spite of Tuesday's revelations that the bout between the pair in Auckland in May would be an eliminator for Williams' NZPBA title.
Williams must fight the number one contender - either Cameron or Barrett - within 12 months or relinquish his belt.
"It's not an issue for us," Nasser said, adding that various parties were simply jumping on the Williams "bandwagon" in order to gain credibility or make money.
Barrett said Williams would be such limited opposition he could successfully fight him and Cameron on the same night but Nasser gave short shrift to those claims.
"Imagine the outcry if Sonny was fighting a 40-year-old with two wins from his last seven fights," he said.
Nasser was conveniently avoiding the fact that Barrett has a 35-win, nine-loss professional record with scalps such as David Tua to his name. He has also been a professional fighter for 16 years and has fought world champions including Wladimir Klitschko, Hasim Rahman, Nikolay Valuev and David Haye.
After Williams' fight in May he has the option of another - probably October after his potential All Blacks commitments in the Rugby Championship.