The trio leads a group of seven players by one shot.
"It's great the way they have supported (the PGA Tour) for 33 years," said Stadler of the new Champions event, which formerly was the BC Open on the PGA Tour. "I love playing here, and I'll always come back."
Stadler was the first to shoot 69, with a round that included six birdies and three bogeys.
Hoch, playing in threesome right behind Stadler's group, made five birdies and two bogeys. Spittle, the last of the leaders to finish the opening round, had three birdies in a bogey-free round.
"I'd like to tiptoe around the next couple of days," said Spittle, who has no wins in his professional career.