At the Morgan Stanley Technology, Media and Telecom conference in downtown San Francisco Wednesday, Nvidia CEO Jensen Huang said his company’s recent investments in OpenAI and Anthropic are likely to be its last in both, saying that once they go public as anticipated later this year, the opportunity to invest closes. It could be that simple. While firms sometimes pile into companies until practically the eve of their public debut in search of more upside, Nvidia is minting money selling the chips that power both companies — it’s not like it needs to goose its returns by pouring even more money into either one. Nvidia, for its part, isn’t offering much elaboration.…