I applaud anyone who does their homework before going out in an adventure like this .
It's not about the 5k tow rating.
You need to pay attention to the payload of your loaded up for a trip SUV as well as the real tongue weight of the TT which includes the WD hitch. Make sure your tire rating can handle the TW.
Many TT's post dry weights . If your real TW of the trailer you buy is double the posted dry weight, don't be surprised. :E
Before you run out and spend money to beef up your SUV TV, aftermarket add-ons such as air bags help, but are only a mask to make things appear level. Those add-ons, if you decide to do that, will not change a vehicles weight ratings or limitations.
Towing a TT down a road in a straight line, with no other factors such as crosswinds, bow waves from overtaking semi's and animals darting in front of you is a different ball game.
When the S...hits the fan, you want your TV to be in control not the other way around.
As an example, if you towed the trailer you mentioned with a 150/250 pickup and ran through a slalom course then did it again with your Nissan, you would feel how the trailer will overtake the Nissan and the 250 will be solid tow. You have to stay safe. Don't be fooled by sales people and posted numbers.
Listen to the folks here that have been doing this safely for many many years. We thank you.