IF you can wait for the OTA Of latest update of Android M 6.0 Marshmallow in your Nexus 5, Nexus 6, Nexus 9, And Nexus Player that was supposed to be coming soon to the Nexus 5, Nexus 6, Nexus 9, And Nexus Player.Then you can download the latest final Preview image 3 of Android M 6.0 from below link and flash them Manually to get the final android M image in your device.
#Download Final Image of Android M Marshmallow 6.0
You can download the TGZ files for a manual flash from Google’s Android Developer page right now.
1.Download Android M final Image for Nexus 5 (GSM/LTE)
2.Download Android M final Image for Nexus 6 “shamu”
3.Download Android M final Image for Nexus 9 “volantis”
4.Download Android M final Image for Nexus Player “fugu”
After Downloading the appropriate ROM image file for your device follow the instruction given on android Site to flash the Final android M preview of Marshmallow from [HERE].
After applying the updates Your device will be updated to latest android M 6.0 Marshmallow Enjoys!.