Instant NuRec turns a short multi-camera driving log into a simulation-ready 3D Gaussian world in a single feed-forward pass. It reconstructs static geometry, dynamic actors, and the sky, supports non-pinhole cameras through 3DGUT, and integrates with NuRec and AlpaSim for closed-loop autonomous driving simulation. A 10–20-second sequence can be reconstructed in roughly 1.5 seconds.