I was not able to find any evidence that Nintendo had their own line of sports games since the original nintendo, if they even did then. It's just that back then all the 3rd parties would work with them. I think that maybe Acclaim's NFL Quarterback Club Series was on N64 and not PS, but I thought it was on Saturn too. And that ended after 99 or so, if it even went that far.
Edit: By the way, I wasn't including Mario Golf or Wave Race as sports games, because they aren't mainstream sports titles, (ie American Football, Basketball, Soccer, Hockey, etc). They certainly haven't had a franchises covering all the bases in a long time.
Edit: By the way, I wasn't including Mario Golf or Wave Race as sports games, because they aren't mainstream sports titles, (ie American Football, Basketball, Soccer, Hockey, etc). They certainly haven't had a franchises covering all the bases in a long time.