The carrier scraper is designed to clean the built up carbon off the surface of the steel and does not cut into it. It should not effect the nickel boron coating. The carrier scraper is made out of 304 stainless steel and you need to use pressure to scrape out the carbon. I havent tried it on a nickel coating to see if it pushes in to the coating and peels it away. I dont know if the polishing pads will damage or remove the coating. They dont have any effect on the steel, but the nickel boron is softer so it may not hold up the the use of the polishing pad.
Some of these coatings are great for wear, but I honestly dont know how they will hold up to the steel tools. All my tests have been on standard finish steel parts and not the specialized finishes. The tools work great removing the carbon and polishing the steel surface but like the parkerizing on the bolt, the nickel boron is a coating and may be scraped off. As much as I'd love to sell you a tool, it wouldn't be worth ruining your finish if it isn't strong enough to hold up to the steel tools. I would recommend holding off until I can get an answer. I will see if I can find a local shop to do some nickel boron for me so I can test it and try to report back.
Hopefully that covers your question but if not, feel free to send me a PM or post another one here. Thanks again for the interest.