Place tortilla quarters on a baking sheet coated with cooking spray. Bake at 350° for 8 minutes or until crisp.
Place sliced mushrooms in a shallow 2-quart baking dish. Drizzle mushrooms with broth, lemon juice, soy sauce, and oil, and sprinkle with basil and thyme. Toss well. Cover and bake at 350° for 15 minutes or until tender. Drain mushroom slices, discarding liquid.
Spread 1 tablespoon Refried White Beans over each tortilla quarter, and top with mushrooms. Top each serving with 1 teaspoon Roasted-Tomato Sauce and 1 teaspoon feta cheese. Place tortilla quarters on a baking sheet. Bake at 350° for 5 minutes or until tortillas are thoroughly heated. Garnish nachos with lime rind, if desired. Serve immediately.