As2S5+HNO3+H2O=H3AsO4+H2SO4+NO
15S(-2) = S(+6) + 120e
40N(+5) + 120e = 40N(+2)
3As2S5 + 40HNO3 + 4H2O = 6H3ASO4 + 15H2SO4 + 40NO
As2S3+HNO3+H2O=H3AsO4+H2SO4+NO
6As(+3) + 9S(-2) = 6As(+5) + 9S(+6) + 84e
28N(+5) + 84e = 28N(+2)
3As2S3 + 28HNO3 + 4H2O = 6H3ASO4 + 9H2SO4 + 28NO
Note - reaction with HNO3 with evolving NO produce elemental S instead of H2SO4.
Yoy can oxidize S to H2SO4 using hot concentrated HNO3 and then NO2 is produced.