Hi @MN19000
Many thanks for reaching us.
Currently we have lpuart_hardware_flow_control demos for the RT10xx series. You can use as reference lpuart_hardware_flow_control of the the RT1060 SDK. This demo simple enables the RTS/CTS pins and uses an config structure. The demo is intended to work on a self loopback mode.

I have not tested this yet, on our RT1176 EVK, but I think the LPUART API should support you to enable this functionality.
If you have issues or further questions do not hesitate to reach again.
Diego