You need the Garmin G1000NXI from the Marketplace to work on third-party aircraft. Make sure it is also updated!
From SU10 Release Notes:
- Important G1000 NXi Note: The G1000 NXi is now default in SU10, however it will only display in default sim aircraft equipped with the G1000. To enable the G1000 NXi in third party G1000-equipped aircraft, please install and/or update the version of the G1000 NXi available from the Marketplace to ensure you have v0.14.