Mitchell was 8 of 11 from the field with 27 points. Tuttle was 6 of 9 from the field, with 21 points. He also had a team-high 10 rebounds. Marc Sonnen added 11 points for the Panthers (2-0).
Northern Iowa had a 41-38 lead at halftime, but Toledo was not done.
At the end of regulation, the score was tied at 70. Northern Iowa scored 14 points in overtime.
The game was the first-ever meeting between Northern Iowa and Toledo in basketball.
Toledo is a favorite to win the Mid-American Conference's West Division.
After a season that saw his shooting numbers slip, should Nigel Hayes return for his senior year at Wisconsin or take the gamble to put him name in this year's NBA draft?
Isaiah Taylor talks about his decision to declare for the NBA draft and what he will miss most about Texas.
Chattanooga women's basketball coach Jim Foster has received a one-year contract extension, the same day the school gave the men's coach a two-year extension.