Howden, 23, was battling for the puck with Predators left wing Filip Forsberg when he lost his balance and took a hit from Forsberg that forced him into the boards headfirst near the Vegas bench with 3:31 left in the first period.
Medical personnel brought a stretcher onto the ice and tended to Howden, who appeared responsive and raised one of his arms as he was taken off the playing surface after a nine-minute delay.
"I thought liberty was taken. He was in a vulnerable position and I thought he got driven into the boards from behind in a dangerous spot," Vegas coach Peter DeBoer said. "My initial concern was obviously about our player. It was a really dangerous hit, and anytime you see someone get stretchered off your concern is there."
After the game, DeBoer said Howden has full movement, adding that he would know more Friday.
Nashville coach John Hynes and captain Roman Josi opened their postgame news conference commenting on the situation.
"On behalf of us Predators players and everyone else, we just want to wish Brett all the best,'' Josi said. "Scary incident there and everyone was a little shocked, but we've heard he's in stable condition and hopefully his recovery goes well. Just want to wish you all the best."
Added Hynes: "I'd just like to echo Roman's statements regarding Brett Howden. On behalf of the Nashville Predators, it's nice to hear he's in stable condition and doing well. We support him and wish him all the best."
Howden has nine goals and 11 assists for the Golden Knights this season, his first with the team.
The Associated Press contributed to this report.