The Pro Football Hall of Famer said just after the Bills superstar quarterback helped secure a victory over the 9-0 Chiefs on Sunday ... Allen "has my vote" for the NFL's highest honor.

Smith said Allen's gotta keep it up for the next two months to really secure it ... but the Buffalo legend made it clear, he's loving what Allen's doing through the season's first 11 games.

"Currently," Smith told us, "as we speak, this is the best that I've seen him play."

Smith, though, said as cool as the MVP award would be for Allen ... he thinks the 28-year-old signal-caller's eyes should be set on bigger and better achievements -- like the Super Bowl.

And, Smith says after Allen and the Bills did what they did against Kansas City -- he thinks a trip to this season's Big Game is now entirely possible.

"I'm hoping that this is what gives us that confidence to know that we can go out on any given Sunday and compete and beat anyone that's on our schedule," he said.