how broad is the term "chipset"?
My understanding of "Chipset" comes from the days where it was literally a set of chips to support a given primary chip, i.e. a x86 CPU (Intel or AMD) and the accompanying Northbridge and Southbridge. The northbridge was the memory controller + high-bandwidth interface(s) (AGP, PCIe, etc.), and the south bridge was the slower I/O.

Modern parts, the northbridge has disappeared to become integrated onto the CPU die (integrated memory controller, PCIe root complex, etc.), and the south bridge, at least in Intel land, has been renamed Platform Controller Hub (PCH). It has extra PCIe lanes, and any I/O to the CPU that isn't PCIe (SATA, USB, etc.), plus interfaces to LPC and the SPI BootROM.

For a FPGA, I suppose you could consider the associated flash memory that holds its bitstream (for SRAM parts) together with the FPGA as a "chipset" but IMO, that is not a valid usage of the term as the SPI memory is not very complex.

For say a cellular system, you could consider the SoC, baseband processor and associated circuitry as a "chipset" as well -- without that combination of ICs, it's not a complete system. The SoC on its own is a very powerful, general-purpose processor but without the associated baseband IC, it's not going to be particularly useful as a cellular phone.

I'd reserve the term for any sufficiently advanced / high-performance ASIC that is required to be used in conjunction with another ASIC in order for the complete system to work.