In a large skillet, saute bratwurst for 1 minute. Add stir-fry blend; cook 3-5 minutes longer or until vegetables are tender. Set aside and keep warm.
In a large bowl, combine cheese and flour. In a large saucepan, saute onion in oil until tender. Add garlic; cook 1 minute longer. Stir in beer; heat over medium heat until bubbles form around sides of pan.
Reduce heat to medium-low; add a handful of cheese mixture. Stir constantly, using a figure-eight motion, until almost completely melted. Continue adding cheese, one handful at a time, allowing cheese to almost completely melt between additions.
Arrange tortilla chips on a large serving platter. Spoon cheese mixture over chips. Top with bratwurst mixture. Serve immediately. Yield: 12 servings.