I have not tried to replace the microusb charging port, but in reviewing the Maintenance and Service guide documentation for the microusb charging jack, it is part of I/O board, identified by part number 761971-001 on page 8. You can also see this part on the Product End of Life Disassembly Instructions as well.
The HP Part Surfer does not list it as available for purchase, but you may be able to find it through an Authorized Parts Partner.
However, since this is a micro usb charging port, I would approach replacing the port itself no differently than you would a phone or tablet.
In the process of searching for your answer, I found How to fix the Hp Chromebook 11, which identifies the connection between the motherboard and battery connection as a cause where the Chromebook itself does not show that it is charging.
Since you have several, I thought it would be a good start to verify that the ports are not working before replacing them.
If you have to change the micro usb receptacle, it is a USB Micro-B. You can find the USB connectors mating matrix on Wikipedia to verify.