I remember about a year and a half to two years ago Nick put out a video saying he didn't believe in sub ohm vaping and that the fad would be in and out. Look at him today, people change their minds and the guy isn't exactly an "expert" when it comes to vaping, for the longest time he had someone else build his coils, even mentions it on some of his older videos.
That said, there is something to the Nickel in wire if the wire gets to a certain temperature, we can achieve that temperature with some of the high wattage builds we have today but the risk is in maintaining said temperature so unless you're out there 24/7 with your finger on the trigger it's unlikely to get you sick but prolonged use hasn't been tested yet so nobody really knows. If you're concerned just stick to kanthal and don'
t worry about it or use titanium for TC builds instead.