How long are you planning on going? Have you birded elsewhere in Bolivia / N Chile / N Arg before?
To get you started, the most visited / most important sites in the NW (assuming you're flying in/out of Salta) are probably:
Lagunas de Yala
Hwy 9 from Jujuy up to the Bolivian border including Laguna Pozuelos and Yavi/La Quiaca
Cuesta del Obispo / Los Cardones NP / Valle Encantado
PN Copo, Taco Pozo (Chaco sites - Joaquin Gonzalez is also popular area but I know nothing about it)
Tafi del Valle / Hwy 307
Los Sosa (near Tafi del Valle)