I suppose if you have a Verizon world phone with the right kind of SIM slot (or a SIM cutter/adapter) and the means to break the carrier restrictions on your device, then yes, you can get it to work on a US GSM network like T-Mobile. It means that you void the warranty and have to do all your own support and upgrades, and I don't know if you can get LTE to work, etc. If someone is asking that question here, it probably means they aren't the type to want to do that, otherwise they'd be on a phone hacking forum trying to figure out the steps for their specific device.
So to the layperson: No, you can't just pop your T-Mobile SIM in any old Verizon or Sprint phone and expect it to work.
Actually I agree with
cckgz4 . If you've been following high end smartphones at all lately on Verizon, they are all 'world phones' coming with the SIM slot factory unlocked - meaning that you absolutely CAN stick in your GSM SIM card (cut to the right size but dollars to donuts it will be microSIM) and the phone will function just fine. SIM card cutters are like $9 on eBay.
This is an agreement they had to sign up to with the FCC when they purchased the 700MHz(c) LTE band - they are not allowed to SIM lock their devices.
Here's the actual text according to the FCC's
CFR Title 47 Part 27.16 paragraph (e):
(e) Handset locking prohibited. No licensee may disable features on handsets it provides to customers, to the extent such features are compliant with the licensee's standards pursuant to paragraph (b) of this section, nor configure handsets it provides to prohibit use of such handsets on other providers' networks.
Believe it or not it was GOOGLE of all people that pressured the FCC in to making this a requirement! Guess we have them to thank for that then eh? (Never thought I'd be uttering those words.....)
Also - given Nokia's long history of making 'world' phones I would say there's every likliehood this will support four of the major 3G bands for the SIM slot (pentaband is still rare as I believe there's one 3G frequencey that's only used somewhere in APAC). Most of the Nokia handsets I've come across support 850/900/1900/2100Mhz 3G bands meaning they will work in the US and Europe. LTE obviously won't work - different radio technology.
I don't see how this would in any way void any warranty or carrier restriction - particularly if you buy the phone outright as you then own it outright (i.e. not tied to a contract sue to subsidized handset). You're not circumventing anything at all to do this, merely putting in a GSM SIM card. And it's been well evidenced in the 920 forum that those people running the 920 on Straight Talk or other MVNO's have received the latest Portico update just as if they were on a mainstream carrier.
Sorry to trash your post but I think you're just factually incorrect.
I for one, will be seriously looking at this handset when it's released as my potential next and I'm currently on Straight Talk.