You can just use the various upscalers within stable diffusion, "Extras" in Automatic1111. Not sure exactly where they're found in Invoke, but they're there somewhere. You can download specialised models for different purposes, and most likely use them in chaiNNer too if you prefer using them there.
https://openmodeldb.info/
I typically use 8x_NMKD-Superscale_150000_G for photorealistic upscales and 4x-UltraSharp for concept art, digital paintings, cgi style. There are many other models ranging from anime, to photoreal, to lineart, etc, etc, etc.