I take chantix too and its working great. I've heard about folks having sleep problems and been told to take your second dose by mid or late afternoon - not at bedtime - to reduce insomnia. Some people take Tylenol PM or Advil PM to help them sleep the first weeks. These are not addictive.
I found that I have good results with only taking one dose/day of the chantix. I apparently don't need the second dose. So reducing your dose might help. but don't risk your quit. If the chantix is working for you then find a way to minimize the side effects and stay on it. I didn't go from 2 doses/day to 1 dose/day until the start of my third week.
Also it is not unusual to have sleep problems in the first weeks of quiting. So hang in there! You will start sleeping better as weeks go by. I am 47 days smoke free and sleeping real well now.
I've also heard that we should wean ourselves off the chantix slowly in our last few weeks of taking it. So reduce your dose, cut pills in half, in the last few weeks. This is to avoid having urges return or feeling "blue" when we go off it. Also been told (its right in the fine print of the package insert) that some folks stay on chantix for 6 months instead of 3 months if they feel like they need it. Quit rates are higher among those who stay on it 6 months. So talk to your doctor if you feel you need an extension after your 3 months are up. All the best to you! Leslie