There is no Niten Ichi Ryu in Texas that I'm aware of.
The Yagyu Shinkage Ryu school will cover both kenjutsu and iaijutsu; it's a complete sword art.
In San Antonio, there is iaido (the modern -dou form of iaijutsu), and there's also several iaido dojo in Lubbock, Dallas, and the Houston area (including Mugai Ryu in Houston). But no Niten Ichi Ryu.