Plane change time at Gatwick

While Gatwick is easier to manage then some airports, I would not risk it.
I love Norwegian but a few years ago they changed my flight time out of Oakland by 55 minutes. I had to change my flight to the previous day AND pay the change fee and a higher fare and an overnight near Gatwick. Because the time change was less than a full hour they would do nothing to help me. (And yes, I still fly them. I had read the fine print!)
Luckily I was traveling for 7 weeks and had some flexibility. (When I amortized the price increase over 50 days it didn’t seem so bad,)
My current rule is now no less than 3 hours between flights on different airlines.

No, it is not enough time.
I recently did a 3h10 change at Gatwick, and I had ~1½ hours spare, but I had a number of advantages over your flights:
1) I was flying from a UK airport, so no immigration to go through
2) I was travelling with hand luggage only, no waiting for my bags to appear.
3) It was a short flight (45 minutes). A transatlantic flight can easily be 1 hour late if the wind is in the wrong direction.
4) I know my way around Gatwick.

According to the Vuelling website "The check-in desks open two hours before, and close 40 minutes before, scheduled departure", so you really only have 1h20 to:
Land, taxi, disembark, walk through corridors, immigration (passports, could be 30-90 minutes), pick up bags, possibly change terminals, and get to the Vuelling check-in.
Do you feel lucky? ☺

Don't do it...3-4 hours minimum change time for Gatwick in my experience. If your first flight is delayed at all you won't make it.

Well Norwegian air flight into Copenhagen was delayed three hours. We made some of the time up but it would make me think what you are proposing is too tight.

My experience is that discount airlines are late more because they have lowest priority at airports and they have no slack built into their systems.

Norwegian is one of the least punctual airlines in Europe and delays of 2-3 hours or more on transatlantic flights are not uncommon. So no, I would say it's not enough time.