It's true that Tim Walz is the third Minnesotan to be selected as a major-party vice presidential candidate, and thus far, Minnesota VP candidates are 2-2 (Humphrey in 1964 and Mondale in 1976).
However, you have to stop there, since both Humphrey (1968) and Mondale (1984) were both defeated in their presidential bids. In fact, in 1984, Mondale lost in one of the biggest landslides in U.S. history, losing to Reagan by 17 million votes (59% to 41%) and losing the electoral vote 525-13.
And that's not mentioning the fact that Minnesotan Harold Stassen ran for president in 1948, 1952, 1964, 1968, 1976, 1980, 1984, 1988, and 1992. And he lost every time.
But I agree that Walz seems an excellent choice, and here's hoping that Minnesota VP candidates go 3-3 in November.
P.S. Here's a Tim Walz fun fact: On Election Day in November, Harris and Walz will both be 60 years old. Walz was born in April 1964, and Harris was born in October 1964.