Looking nice already!
One piece of constructive criticism; I'd add more really tiny chips and also check where you've placed your chipping.
Your chips are quite large and some areas remain almost undamaged, whereas you might expect more small and really small scratches and chips as well. My experience is that adding really tiny chips add a great deal of depth and realism. Patience is key; if you add chips and think you can hardly see anything happening, you're doing it right; all these really tiny chips (use e.g. sowing pins and toothpicks and rub and scrape/schratch slowly and gently) together will really add depth and detail eventually.
Chips should be most prominent in spots where trees, branches, rocks etc. would hit the machine (lower legs, outside edges of the legs, front of the round 'cheeks'). Also battle damage would logically be more visible on the front.
btw. I've never heard of using cinnamon for rust, but you can use weathering pigments (fixate with Tamiya X20A) to get a nice rust texture.