Mayweather told his business partners to get their "chequebooks" out soon after Nurmagomedov's initial call-out and then insisted to TMZ the fight would happen.
The fight would be Mayweather's second against a mixed martial artist, having defeated Conor McGregor in the tenth round of a similar crossover bout in 2017.
Mayweather, who boasts a ideal 50-0 record and the unbeaten Nurmagomedov (27-0) would be certain to generate another bumper payday if they do fight.
I don't know any fighters that have made the money I have made.
"We're fighting", Mayweather told TMZ Sports. He knocked out England's very own Ricky Hatton in devastating fashion but I don't see it.
Nurmagomedov and McGregor have both been temporarily suspended by the Nevada State Athletic Commission pending a full investigation into the scenes that marred the end of their fight in Las Vegas.
In the 41-year-old's defence, it probably makes more sense for the fight to take place in boxing and Mayweather is certainly the bigger pay-per-view draw.
Either way, the brief back and forths between the two has, of course, created discussion among the MMA community as to what would happen if the UFC lightweight champion Nurmagomedov were to step into the squared circle. Only one king. Of course, I am the king because he can not drop McGregor but I drop him easily. Because in the jungle, there's only one king.
Mayweather thinks he will make even more money fighting the Russian than he did when he took on McGregor.
"If you decide to fire [Zubaira], you should know that you'll lose me, too", he said. "I'm gonna say somewhere between $110-$200 million guaranteed".
"Unless he's just going to go do it for money, because he is going to get beat". Khabib is going to start wrestling in the boxing ring.
A better fight, if Mayweather is serious about returning to the ring, would be the newly-crowned highest paid man in the sport Canelo Alvarez.
Mayweather quickly responded to the challenge on Twitter, which caused bookmakers to set lines for a potential boxing match.