This is not a healthy way, but a unique one that might work. I don't have insomnia, but I do have trouble waking early in the morning, so sometimes when I have to be up real early for something particular, in fear that I might not get up, I pull an all-nighter (zero sleep at all, not even a 1-hour nap). Then I make sure that I don't take any naps the next day, using coffee or whatever I have to do to stay up that whole day, surviving until 9 or 10 at night. Then go to sleep at this point and I am so exhausted I can sleep in any condition really (lights on, clothes on, doesn't matter, if my head hits a pillow I am out cold). As long as you get through the entire next day without any nap, you will be so exhausted by 10pm that night, that you will likely pass out quite easily.
I find that the following day, (after the allnighter, after the 10pm lights out), I will wake up sometime in the morning, but when 10pm rolls around the next night, I am programmed to be tired and get to bed then just like the night before (even if I was habitually going to bed at 2 in the morning prior to the allnighter). It is like a shortcut way to force the body to tire earlier at night. shock it with the allnighter, then stretch it out til 10pm exhausted, then after a full night's sleep, the following day the body will be accustomed to go to sleep again about 24 hours later, so at 10pm you will be tired.
I feel like if you get tired enough the insomnia will be overpowered and become irrelevant, since there is a certain involuntary nature in the allnighter-recovery sleep, which I have experienced, but I don't know much about insomnia at all.