I've found my slow cooker doesn't get hot enough to soften some vegetables like onions, peppers, or carrots. I know you didn't mention a texture problem, but I'm mentioning as an example that slow cookers cannot be used to replace other methods of cooking.
A saute, besides browning meats and vegetables, will also soften veggies and drive out excess moisture. In a slow cooker, the moisture goes right back into the dish, diluting the flavors.
Is that ground chicken? That sounds like a chili recipe without beans. All the liquid that given off by ground meat usually gets drained. Not so if you toss it in a slow cooker.