Rub sweet potatoes with 1 1/2 teaspoons oil; pierce several times with a fork. Microwave at HIGH 12 to 15 minutes or until potatoes are tender.
Heat a large skillet over medium-high. Add remaining 1 1/2 teaspoons oil; swirl to coat. Add onion and red bell peppers; cook 5 minutes or until tender, stirring frequently. Add garlic, and cook 3 minutes, stirring frequently. Stir in chili powder, 1/4 teaspoon salt, cumin, and ground red pepper. Add beef; cook 6 minutes or until browned, stirring to crumble.
Preheat broiler to high.
Heat broccoli according to package directions; stir into beef mixture. Arrange potatoes on a baking sheet. Partially split potatoes lengthwise; fluff the flesh with a fork. Top potatoes evenly with beef mixture, remaining 1/4 teaspoon salt, and cheese. Broil 30 seconds or until cheese melts. Sprinkle with green onions.