Rattlesnake Chili

3/4 cup chopped onion
3 tablespoons oil
2 1/2 cups parboiled rattlesnake meat
2 cups cooked tomatoes
2 cups cooked pinto beans
2 1/2 teaspoons chili powder
1/2 teaspoon hot red pepper flakes
1 teaspoon salt

In a large skillet, saut