The documentation for the hardware should describe the type of chipset used.
If you don't know what type of chipset you're using, you can identify it using pci -vvv.
Find the entry for the Network controller and it'll give you details on the manufacturer/vendor ID and device ID. Either find the information on the manufacturer's website, or use the vendor ID and device ID to cross-reference it with this online site: https://www.pcilookup.com/.