Ugh....Swaying?

If I remember correctly, your truck has "P" rated (passenger car) tires. They can create a lot of movement.
A set of E rated LT tires would help but you may need to adjust your WDH more as well. It's really hard for anyone here to know without experiencing it first hand.

What is the tongue weight like? Having too much will raise the front of your TV (even with WDH), removing a lot of traction from the front steering wheels, and possibly causing your sway issues.

Yes, I have the P rated tires...the dealer never mentioned anything about tongue weight. The front of the truck is a little high when connected. He said I would be fine with that.

Not enough truck for that size trailer. You need more truck weight and more power. You are most likely maxing out your trucks capacity if not going over it.

Your truck is rated to tow a max of 6500lbs depending on configuration. This trailer will be pushing that limit loaded probably.

Thats a lot of trailer for that nissan. Nissan states 6500 lbs. Thats a 7000 lbs trailer.

Probably weak suspension and the WD is not set up properly...

IMO they should have never sold you that trailer with the truck you have..

This would have been a better option in what you probably were looking for..

Plus its 1500 lbs lighter..

http://www.jayco.com/products/travel-trailers/2014-jay-feather-ultra-lite/x213/

Your truck is a bit small for that size of TT, but it's what you got.

Check the tt tows level or slightly nose down.
Do you have enough tounge wt?
Is the wdh set up well. If the dealer did it then there's a good chance it's not. I have receintly had some friends who were "set-up" very poorly from the dealer resulting in a scary tow.

I tow with a Pathfinder, which is mechanically identical to your frontier, and I have to agree with kmbelt. I wouldn't tow anything bigger than 5000lb gross with the Pathfinder/Frontier platform.

Without knowing what WD/anti-sway hitch you have, it's hard to say if the hitch settings had anything to do with your sway, but I don't have any problems with my 5000lb, 24-foot trailer with the Pathfinder and Equal-I-zer hitch combo. I use the standard P tires as well, regular inflation. Some Frontier/Pathfinder owners who tow at the limit have recommended air bags in back to stiffen up the suspension, so you may give that a try.

Also how fast were you going? The faster you tow, the more likely to sway, especially if you don't have enough TV. I usually tow at 60-65mph on the interstate with my combo.

It can be a bit of work to get your tow set up right, and inexperience doesn't help. See if there is a local RV club, with someone who can drive it and appraise the feel. There are way too many things to adjust on the hitch alone (height, head angle, bar weight, bar tension) and issues with weight and balance on the trailer, there is some trial and error to get it set up right.

The TT dealer should have worked this out, but a tow can feel just fine to the guy who set it up and test drove it, yet be scary to a new driver. Don't go buying new tires for your truck until other things are sorted out, there just isn't that much difference in stiffness P tires vs LT tires in that small a size, when inflated the same.

But tongue weight could also be the problem, i.e. too much for your payload, and that would call for tires that can carry more, wheels that can handle the tires, and suspension mods. It may be simply that the dealer sold you too much trailer for the truck.

I see a dry weight of 4300lbs, so loaded approx 5500lbs. I wouldn't call that over your limit, but probably the max you'd want to tow.

Sway is often too little tongue weight, also the WDH may not be set up properly. Some brands of hitch have the option to put a friction sway bar on both sides. With the length and weight trailer you have, it may be beneficial.

New truck tires will help as well.

Thanks for all the info. TT is rated at 4365 dry weight, so it is pushing the limit with gear, although I haven't put anything in the TV or TT. It was all set up by the TT dealer. I've called them, they told me that I needed different tires. One fellow told me it was because I was new to pulling (which I agree) but I would rather be comfortable with towing then scared sh*tless when towing. I will have to see who the manufacturer is for the WD hitch. Never got over 60MPH. Way too scared to go any faster. :)