Nilstorp was the backup to Richard Bachman before Tuesday's move. Bachman has made three straight starts since he had to replace starter Kari Lehtonen, who re-injured a groin early in a win over the Los Angeles Kings on April 9.
Bachman helped the Stars finish off a season-best five-game winning streak before Monday night's 5-2 loss to Chicago.
Nilstorp has bounced between Dallas and the Texas Stars most of the season. He's 1-3-1 with Dallas and 18-11-5 with Texas.
The Stars have two days off before playing Vancouver at home on Thursday night.
That's a really tough thing to play through; when you finally are thrown out there, the game is fast, intense, every single play matters, you've got to find a way to play through that and make smart plays. So it's a huge testament to [Vermette] and some other individuals in our locker room that are putting their own ego, their own wants and needs aside, and are ready for those opportunities when they do come.
— Blackhawks captain Jonathan Toews on teammate Antoine Vermette, who returned from being a healthy scratch in Game 3 to score the double-overtime winner in Game 4