The former Mamelodi Sundowns captain was amongst the panel of speakers during the Nedbank Cup Football Finance Summit held in Sandton on Thursday.
Other panel members included Mark Williams, Daine Klate, Benni McCarthy, Absolom Thindwa and agent Glyn Binkin.
Nthethe has since taken to court one of the well-known businessmen in Bloemfontein in a bid to reclaim his money after their business venture fell down.
"Players need to ask questions. I used to tell myself that I know these things, that I can manage my money well. Going that route you find out that you are doing a terrible mistake that you are not anticipating," Nthethe said.
"Players must find solutions how to get help and how they can invest. You can invest into other things and you find out it's a bad investment.
"I also invested into someone's company thinking that person cannot do a bad thing with my money. He is a person that has money. South Africa knows him and till today since 2016 I don't have that money. It's a lot of money."
Nthethe has been training with Tim Sukazi's Galaxy in the hope of securing a contract with the club, which has brought in Mabhuti Khenyeza as their new head coach.