charger port is broken

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.

VTech InnoTab Max Motherboard Replacement - iFixit Repair Guide

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.

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.

VTECH INNOTAB MAX MICRO USB CHARGING CONNECTOR SOCKET PORT DC JACK BLOCK - eBay

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.

20Models Micro USB 5pin Female Connector For Mobile Phone Charging SMT Socket Data Jack Connector Port PCB Board Drop Shipping

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.