Many people will disagree with this, but I have not found an RTA that I enjoy nickel builds on, and yes, to everyone that might ask, I know exactly how to build nickel coils. RTA's, or most atty's for that matter, are just not designed to be used with nickel. Ni coils are far to finicky, and everything has to come together almost perfectly for them to work correctly, something that can be a challenge in an RTA. It isn't impossible, by any means, but it usually leads to more frustration than enjoyment.
My choice for utilizing temperature control is in an RDA (the Holmes V2 is my current go to), specifically one with a 2 post design to accommodate the larger coil you are going to need to build. With an RDA you have much more control over the contributing factors (airflow and wicking) that TC needs to work correctly.
With my Holmes I build a 26g 14wrap around a 6-32 machine screw and it fits in the posts perfectly. I think it ohm's out at about .13 if I remember correctly and I can vape it at 40watts without hitting TP.