Not sure if it has changed from 2014 to 2015, but the Nissan web page states that a SV 4WD with the tow package has a max tow rating of 6500 pounds.
You say that your trailer has a dry weight of 5500 lbs. Did you actually weigh it to get that figure, or is that from the manufacturer? If it is from the manufacturer, it is probably low; they typically are. Plus, even if accurate, that is the weight of your trailer with nothing in it. To that, you need to add batteries, propane, residual water in your tanks, your hitch, any random stuff you have in the trailer (chocks, hose, stabilizers, bedding, linens, dishes etc.). Then, you start adding weight of the contents. Food, lawn chairs, gas for the toys, etc. Then, add the weight of the toys. How much does each toy weigh? How many do you have? I'm going to guess that you'll end up weigh over 6500 pounds when you're all done.
The best thing to do is load up your trailer like you're going camping, including your toys, and drive down to your local truck scale and get an actual weight.
Also, what kind of hitch are you using? I highly recommend you use a high quality weight distribution / anti-sway hitch. I use the Equal-i-zer brand; Reese also makes one, called the Dual-Cam hitch. I believe there is a company called Blue Rhino that also makes one. And, the Cadillac of hitches is the Hensley hitch, but that will run you about $2000. Finally, what kind of brake controller.
The Armada makes a terrific tow vehicle, probably the best 1/2 ton SUV out there for towing. But, remember, it is just a 1/2 ton SUV. It's real easy to overload it, because of the power and capabilities of the truck. Be very careful.
Oh, and welcome to ClubArmada!
Keith