Probably not. Pudendal nerve entrapment is unlikely to be effectively treated using an inversion table although the nerve pain might feel better temporarily while inverted.
Depends. If the nerve irritation is coming from higher up in the spinal cord, it may help. However, if the nerve impingement is in the buttock or pelvic area you might not see much difference. Other stretches or pelvic physcial therapy can help with this.