Replacement for TSM2323 MOSFET
When searching for replacement, you should look at the first few words of the transistor datasheet. In this situation your keyword is ultra low on resistance. I seached for digikey with similar r ds on resistance. I found that Si3433CDV has very similar characteristics with your transistor. In general, if Vds and Vgs graphs at the datasheet are similar you can use that MOSFET for replacement.