Nuance is just a VARIATION. Like the colors red but if you add to it's still red. It's still a color. Just different. Like a human who speaks English, but with an accent. Its a small but SUBTLE difference. I guess you can conclude that any topic or subject thing can have different variations and small changes can make it different in many ways.
If you understood nuance and subtle, your political analogy would be the basics ones with many variations and combinations that you could easily accept. In math such things are called sets, and subsets of those sets. Or a basic formula with many unknowns to be identified and solved for.