Copy the Pic-a-Pix Deluxe NSP into that folder.
If you prefer a secure, legal version with official updates and DLC access: Pic-a-Pix Deluxe Switch NSP Free Download
To use NSP files, your Nintendo Switch must be running like Atmosphere. A Modded Switch: Must have a working homebrew environment. SD Card: Formatted to FAT32 (recommended for stability). Copy the Pic-a-Pix Deluxe NSP into that folder
The digital "cartridge" file for Pic-a-Pix Deluxe . Pic-a-Pix Deluxe Switch NSP Free Download
Open NS-USBloader on your PC and drag the Pic-a-Pix Deluxe NSP into the window.