It's not the styling (which is entirely unrelated), it's the platform - GA-B front, GA-C rear.
Cars that share platforms usually share hardpoints for mounting mechanical components, like suspension, gearbox, and... engines. Thus what works in the GR Corolla (and at a push the GR Yaris, as they share the 2JZ in-game) should work for the C-HR.
Fitting is often a matter of time, money, engineering skill, and MacGyver. But most swaps in GT7 (not all, as far as I'm aware) represent real builds. Not always in a real fashion - the Beetle needs its back seats out for an H6 - but in spirit.