A quick Primer on disc dynamics...
Just a few pointers about the Innova disc rating system, which I find to be the best:
1. Speed: This is the relative "speed" of the disc out of your hands. Also known as "wrist snap", the faster your hand/wrist speed, the "faster" disc you can throw. A speed 13 disc is designed to be thrown with much more wrist snap/hand speed than a speed 10 disc. All other ratings listed below are driven by the speed rating, so if you are throwing a 13 speed disc, like a Boss, Groove or Katana without the appropriate hand speed, your performance will suffer greatly. This is why many people get frustrated with these discs, as they just don't have the wrist/hand speed to get the disc to fly right.
2. Glide this is the amount the disc will glide with the wind. A higher glide rating will mean the disc will tend to stay in the air longer than one rated lower. This is a highly subjective rating, as conditions like headwinds, tailwinds, and cross-winds can affect this rating.
3. High Speed Turn: This is the "counter turn" which is the initial turn out of your hand. A typical forehand throw (right handed) will start to the left, then fade hard right at the end of the throw. These numbers are rated with a negative number, so the lower this number, the more "understable" the disc is. This rating is relative. So a 0 rating means the disc will not turn as much as one rated -4, which will turn quiet a bit.
4. Low Speed Turn/Fade: This is the rating for the fade of the disc when it runs out of energy. Once again, this rating is relative. These numbers are positive, the higher this number is the more "overstable" this disc is. All discs fade, even discs that are rated 0, like a Mako or a Dart. Keep this in mind for putting.
As far as a learning player, some good rules of thumbs:
1. Don't go crazy buying high speed discs. You said you bought a Nuke, which is a very high speed disc, so I would stay 10 and below for now. Higher speed discs are more sensitive to throwing errors, and thus are much harder to control with any consistency.
2. Tune your bag for different conditions. For instance, it might be a good idea to carry both a Tee Rex (11/4/0/4) and a Monarch (10/5/-4/1), as they basically are opposites and would be appropriate for different types of throws. For instance, you would use the Teerex on a hole that has a sharp right turn at the end, while the monarch would be useful for holes that fade to the left (assuming you're throwing a forehand right handed).
3. Use several putters and mids. I use a Dart(3/4/0/0), Mako(4/5/0/0), Stingray(4/5/-3/1) and Buzz(4/4/0/0) as putters/mids for differing conditions. The stingray is great for longer putts.
4. Have fun, and always remember, a bad day of disc golf is better than a great day at work!