This usually implies a conflict with existing game mods or a corrupted install.
To apply the update to your Switch console, you will need the base Miitopia NSP game file and the separate 1.0.3 Update NSP file. Follow these standard installation steps: Prerequisites miitopia switch nsp update 103
Press X on your Switch to stop the MTP responder once finished. Method 2: Installing via Tinfoil This usually implies a conflict with existing game