1. Stir together first 6 ingredients and half of French fried onions; spoon mixture into a lightly greased 4-qt. slow cooker.
2. Cover and cook on LOW 4 1/2 hours or until bubbly.
3. Heat pecans and remaining half of French fried onions in a small nonstick skillet over medium-low heat, stirring often, 1 to 2 minutes or until toasted and fragrant; sprinkle over casserole just before serving.