Yes, sweating noticeably from the foot pads can be caused by nervousness. It's said that the damp foot-pads (dogs and cats) provide greater traction in case the animal has to run.
Try not to let that upset you. I am sure your lovely rescue dog will relax a little more each day as she gets used to her new life and family.
Maybe she had to go through some stressful things in the past (?) and it's not easy for her to place her trust very quickly.
Be kind, but don't crowd her with too much emotion...grabbing....hugging....sudden loud noises, etc. Just gentle kindness, affection and routine will help her.
Dogs have few sweat glands but mist are in their feet along with oil glands. The dog could be hot, just have a high metabolism or nervous. From what you describe, it could easily be due to feeling anxious.