I just checked Washington State record last year. they were 6-6 with a bowl with against Utah State. not overly impressive overall.
However, they went to Mississippi in mid-October, who was ranked #4 at the time and lost by a field goal. So, it sounds to me like this coach (and his tranfser portal players) know how to play the underdog well. BTW, does anybody know how many of the ISU starters were starters/players for Washington state last year? It might make a difference for continuity.
I still expect a very close game. I've seen this movie WAY too many times in the last almost half century.