Do you have an English translation of the nixie tube spec? I see 115-170 B which is probably the voltage and <=2 mA which could be the anode current (min? max?). If that is the case, then the second and third power supply would be fine if you can reduce the output voltage; It says 64 mA at 180V. The first supply doesn't spec a current, but since it is intended to drive a clock (at least 4 nixie's) it should be fine also.
BCD to decimal shouldn't really need a library. Connect 4 output pins to the A, B, C and D inputs of the chip. Connect the chip pin '1' to 'cathode 1' or 'k1' of the nixie, pin '2' to 'k2' etc. When you want to display '0' set all 4 output pins low (0 0 0 0). To display '1' set all low except set A = high (0 0 0 1) etc. Use the table in the datasheet for each digit 0 - 9 SN74141N pdf, SN74141N Description, SN74141N Datasheet, SN74141N view ::: ALLDATASHEET :::