This model can be run completely offline, yes. You'll need anywhere from 60-200 gb of RAM (either VRAM for high speeds, or a combination of VRAM and RAM, or just CPU+RAM). The active params are really low (3B) so it'll likely run fine even on CPU. Should get 10-15+t/s even on old DDR4 systems. Offload some experts to a GPU (can be as low as 8-16gb) and you'll see greater speeds.

This has nothing to do with nano banana, or image generation. For that you want the qwen image edit[1] models.

1 - https://huggingface.co/Qwen/Qwen-Image-Edit