Dev,
First, you are going to need to determine which Zigbee/802.15.4 Protocol and Profile the NRF 52840 is implementing in its code. Once you know that, you can adjust the XBee modules settings as needed. For example, the ZS parameter will likely need to be adjusted to either a value of 1 or 2. Other settings such as EE and KY may need to be adjust depending on which Profile is being used.
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