According to the documentation, your charging port is a fairly standard micro USB port, but it is mounted on the motherboard so replacing it will require you to remove the motherboard first.
[guide|79862|VTech InnoTab Max Motherboard Replacement - iFixit Repair Guide|new_window=true]
Once you have it out, you will have to be somewhat handy with a soldering iron in order to remove the old port and replace it. Here's the part you need to swap out.
[image|3324464]
The hard part may be locating a suitable replacement part; the only one I found that says it's specifically for the InnoTab Max is on eBay in the UK; here's the listing.
[link|https://www.ebay.co.uk/itm/132470276750|VTECH INNOTAB MAX MICRO USB CHARGING CONNECTOR SOCKET PORT DC JACK BLOCK - eBay|new_window=true]
Or you could take a shotgun approach and just buy a bag of assorted ones like I did to fix a room filter fan for my son.
[link|https://www.aliexpress.us/item/3256805453740106.html|20Models Micro USB 5pin Female Connector For Mobile Phone Charging SMT Socket Data Jack Connector Port PCB Board Drop Shipping|new_window=true]
If you're somewhat experienced at soldering this shouldn't be too bad of a repair, but otherwise you might have to find a local repair shop; most of them shouldn't have any trouble swapping this part out for you.