The Autodesk® Civil 3D® guide includes the following sections:
NOTE: LAS format is no longer supported as import format in Civil 3D. Read the AutoDesk article here: https://knowledge.autodesk.com/support/civil-3d/learn-explore/caas/sfdcarticles/sfdcarticles/LAS-format-files-no-longer-import-into-Civil-3D.html.
The suggested workaround is to use Recap to insert a LAS file as a Point Cloud into Civil 3D. More info: https://knowledge.autodesk.com/community/screencast/be70a190-0089-4125-811f-0d43b15953d5.
Autodesk Civil 3D is not Nearmap product, and as such any support you may need should be directed to Autodesk. Check out Autodesk's Knowledge Network at: https://knowledge.autodesk.com/.