Hi,
if you need to have access also to Nexus connector for tracing, it is necessary to select 256BGA package. Smaller packages have not such option or it's necessary to use vertical setup. The EVB boards can be found here:
https://www.nxp.com/design/development-boards/automotive-development-platforms/mpc56xx-mcu-platforms...
If you are looking for whole kit (motherboard + daughter card) this is the right part number: MKT564B256BSB3M
I can see that versions with sockets are not available anymore, there's only option with soldered MCU.
Anyway, MPC5646C is relatively old product, period for guaranteed availability ends in 2026:
https://www.nxp.com/products/product-information/product-programs/product-longevity:PRDCT_LONGEVITY_...
If possible, I would consider newer devices like MPC57xx or S32K1 or S32K3.
Regards,
Lukas