Pretty shit for a computer. He says his 50m model reached 1800 Elo (by the way, its Elo and not ELO as the article incorrectly has it, it is named after a Hungarian guy called Elo). It seems to be a bit better than Stockfish level 1 and a bit worse than Stockfish level 2 from the bar graph.
Based on what we know I think its not surprising these models can learn to play chess, but they get absolutely smoked by a "real" chess bot like Stockfish or Leela.