That’s a hard one because I’ve never experienced it before myself. I guess it depends on what you mean by ‘going nuts’. My assumption is that the longer you keep them inside, the more they adapt to the lifestyle and the easier it will become. You could also build a cat run / outdoor enclosure for them, or leash and harness train them to go on walks. I’ve had good experiences with using feliway to help calm cats too - that may help. If the issue is that the kitten is territorial, then it might help to set up a private area for them and ensure that they have their own separate litter box that other cats can’t use.