Ground beef usually has quite a bit of fat. You could try it with either ground turkey breast or ground chicken breast. You will end up with a lot less fat and fewer calories. The downsides in a culinary sense are 2: the texture of the poultry will not be quite the same as ground beef and the flavor will not be quite the same. You can pretty much get the flavor by using some beef base for the beef flavor. I think the poultry works pretty well because chili is generally spicey enought that the difference between beef and poultry will not be that big a deal. Of course, you are the one eating this so it is YOUR call.
You can also use leaner ground beef. Grass fed beef would even increase the level of omega 3s.