It would help if you told us what the protocol listing these
buffers was for. An ISH protocol I have lists TNT buffer as 0.1 M
Tris-Hcl, pH 7.5, 0.15 M NaCl, and 0.05% Tween 20.  TNB may be
0.1 M Tris-Hcl, pH 7.5, 0.15 M NaCl and 0.5% Blocking reagent.