Nipsey Hussle was in the middle of a good deed right before he was gunned down in front of his store ... where he was trying to help out an old friend who just got out of prison. Sources connected to Nipsey tell TMZ ... the reason he was at his Marathon Clothing store Sunday is because he was trying to hook up his ex-con pal with some new gear so he could look good before meeting up with his own family and friends later in the day.