Where is the internal storage located on motherboard?

Hi @nimchip

Don't know the answer and as Nvidia doesn't release the schematics to the public I can only suggest that you open the tablet and remove the shields covering the components on the motherboard and hopefully they will have markings on them that identify what they are i.e. component manufacturer's make and model number or part number etc, and that you search online using use that information to find out what it is e.g. nand flash memory chip

Here's the ifixit Nvidia Shield Tablet Motherboard Replacement guide, that may help.