i have a 2010 nissan and when i drive to about 65-70 mph the steering wheel seems to begin to shake or vibrate. I am thinking this could be either my tires or ball joints?

Sounds like possibly a tire out of balance.

Good call on a tire out of balance. Sometimes those wheel weights do not adhere to the wheel well and you can easily sling one off. That would cause the tire to not rotate perfectly and you can feel that vibration through the steering all the way to the wheel. I would be curious if you could still feel it at 50 mph or so, just that it's not nearly as bad. Or once you get it wound up on the interstate, all of a sudden, BAM there it is? Any tire shop, or mechanic should be able to balance your tires and check wheel weights. Also, you can check to make sure your tires are wearing evenly. Poor alignment shouldn't cause that feeling that you have, but because of this issue, you may have a tire wearing abnormally.