I'm doing something similar right now but you might need to bake the material (your nodes) to a texture. This tutorial explains it well (you can skip the information at the start but it is helpful knowledge). Or just look up a tutorial, there are many great ones out there but the basic idea is:
- Change to cycles
- Under the Render tab (in the properties tab, often on the right-hand side)
- Under Bake, set bake type Diffuse and only select the colour under influences (Direct and Indirect should be disabled)
- In your shader window add a vacant image texture floating unattached.
- Hit new. Name it. Set texture resolution in height/width (should be 1k by default)
- In image editor (drag open a new window and select if it's not there) and select the image texture to see the result.
- Then hot N over the window and change colour space in the menu to sRGB
- Go back to render settings and hit Bake
- Save or discard it in the N menu
It could also be the addon. I haven't heard of it but if you send me a link and can confirm if that's most likely your problem or not!
Have a good day :)