Argenis Mendez of the Dominican Republic and Arash Usmanee of Afghanistan battled to a 12-round draw in Verona, New York, on Friday night.
Mendez retained his IBF junior lightweight title in the main attraction of Tyson's marketing debut.
Tyson, a member of the Boxing Hall of Fame, heads Iron Mike Productions, and his aim is to be a full-service agency for up-and-coming fighters who can learn the sport, in and out of the ring, from one of the greatest.
The tournament, dubbed Tyson Is Back, disappointed some fans who felt Mendez won the bout. Iron Mike was one of them.
"I'm very grateful," Tyson said. "We had two sensational championship fights. I thought my fighter (Mendez) won his fight. It was a sensational fight, good for boxing, but horrible for my boxer. He's a great boxer."
In another bout, Jesus Andres Cueller outlasted Claudio Marrero to win the vacant WBA interim featherweight championship.
But the story of the night was Mendez and Usmanee. Neither was knocked down. "I'm really disappointed in the decision," said Mendez, whose nickname is La Tormenta. "I'm the champion and I thought I won."
"It was a very close fight," Usmanee said. "It depends on how you judge a fight. I was the aggressor. It could have gone either way."
Tyson said he was ecstatic to be back in the sport. His fighters would not be subjected to what he went through in his heyday, he added.
"When I first got involved, I just didn't know," Tyson said. "Never in a thousand years did I plan on doing it. I'm just happy to be back involved in boxing. It's a dream come true. I'm a little nervous."
Tyson, 47, who has battled addiction and depression, and lost millions of dollars through the years, hopes to provide his fighters with a structured environment for success, and to help them learn from his mistakes.
"You're never going to hear them say 'Mike Tyson stole from me.' Hopefully, they'll never end up like me," he said. "I'm not a magician. The only thing I can do is suggest; go in the right direction. We have to look for happiness within. I can't stop somebody from hurting themselves."
In other bouts, Eddie Paredes (34-3-1) posted his 12th consecutive victory, defeating Noe Bolanos (24-9-1); Alexei Collado (17-0) beat Guillermo Sanchez (13-10-1); Dorsett Barnwell (10-0) stopped Marlon Hayes (23-13) in the third round; and Antoine Douglas (9-0) beat Edgar Perez (5-6).