Nicrhome and nickel are two totally different metals.
Remember the basics... Kanthal and Nichrome are primarily wattage only devices. TC works by detecting the resistance change once it heats up. Because of the mixture of metals, they cannot have a steady resistance change while it heats up.
Stainless steel is primarily used in TC, but has been known to be used in wattage mode. It is also a mixture of metals, but since stainless steel has been around for a while, there are certain "recipes" to make a particular type of metal, and can be accurately monitored... assuming you're using the correct type of steel.
Nickel and Titanium are pure metals and decent conductors. Their resistances are too low to be used effectively in wattage mode. There is also some danger for titanium using wattage, since if you get the coil too hot, titanium dioxide might form, and that is a hazardous element.
On a side note... Titanium is also flammable. I have taken some titanium wire, and put a blow torch to it outside. It burns a bright white light, and will keep burning for a while.. somewhat like a really bright fuse. I don't advise doing this on a regular basis, since the smoke is toxic. Titanium is what is used in fireworks to make a bright white light.. copper is used to make a blue one.
