[Nexus 6  General] ooofest:
I might as well summarize my experience with Verizon and the Nexus 6 thus far, since it's probably typical in many respects:

Getting a nano SIM for a phone that Verizon doesn't yet recognize:

Purchased a new, carrier-unaligned Nexus 6 that came from the Motorola website (64GB Midnight Blue), which obviously comes with no (nano) SIM card

My old Verizon phone, a Samsung Galaxy S III, used a Verizon micro SIM card

Experimenting with cutting a (different) micro SIM card down to nano SIM led to disaster for the card, though I did try to be careful. Decided that the manual cutting path wasn't for me. Maybe one of those punch-out cutters are more foolproof

Obtained a free nano SIM card from Verizon after calling Technical Support and telling them I got a Motorola that will require nano SIM format, for my existing line. They sent it via two-day FedEx.

Trying to activate a new Verizon Wireless nano SIM:

Learned that you cannot place a nano SIM card into a non-nano SIM phone and activate that SIM with Verizon - their online and phone-based activation methods both use the same check to determine if a SIM card is physically the same size as required by the phone. So, even using a nano-to-micro SIM adapted in a micro SIM phone won't fly for first-time activation of a nano SIM

A Technical Representative on the phone told me that one of her co-workers was testing out the Nexus 6 internally (as part of their job) and they really liked the phone, it was working well with their systems, etc. But, you couldn't register the phone with a consumer account, yet. I was also told that unaffiliated Nexus 6 phones (such as mine) should be formally accepted and recognized by Verizon after they open their systems to registration for that model.

I was able to obtain a used Moto X (2013) and activate my new nano SIM on my Unlimited Data Plan phone line using the Verizon Wireless website. I waited until the My Verizon website showed that I had a Moto X on the line, just to ensure everything was cool

Activating the Motorola-bought Nexus 6 on Verizon's network:

Placed the newly activated nano SIM into my Nexus 6 and went through phone activation on Verizon's network for the first time. It was showing a progress indicator for about two minutes . . . then, it moved to the next step of setting up phone configuration, Google ID, etc.

The My Verizon site now shows my line as having an unknown phone with the Verizon SIM, and an additional warning states this condition in more explicit - but non-threatening - terms.

I've been able to use phone and 4G data features on Verizon's network without problems on the Nexus 6 since activating with the nano SIM.

After Verizon officially recognize Nexus 6 phones in its system, I'll check back and ensure that my phone is propely recognized by them, in case network issues crop up and I need formal support in that regard. Obviously, I am not asking them for phone support, as I'll get that through my Motorola warranty.

So, I'd imagine the steps above for registering a Nexus 6 with Verizon will become

Bring your Nexus 6 to Verizon (i.e., they ask for the IMEI)

Ask for a new (free) nano SIM if you don't already have one

Place the new nano SIM in your Nexus 6 and activate both with Verizon either online or via Phone/in-Person Representative

after they formally recognize the phone :) .

I don't know if they'll give former AT&T or other carrier Nexus 6 owners a hassle in using their phones on the Verizon network due to IMEI, though.

- ooofest