Men can compete in women's events "after completing one calendar year (12 months) of testosterone suppression treatment." There is no mention of testosterone levels or any other measures, so fencing is now wide open for a Lia Thomas situation.
The CEO has gone full in for transgenderism:
“It is critical that we protect the rights of nonbinary and transgender athletes in fencing,” said Phil Andrews, USA Fencing chief executive officer. “Even as we plan to conduct more scientific research into the physiological effects of gender transition as they pertain specifically to the sport of fencing, we remain unanimously and steadfastly supportive of transgender athletes having their place in fencing. To be clear, even as this issue evolves, our support of transgender athletes will not waver.”
The nonbinary policy is a bit confused. It essentially says that they must become binary again:
Nonbinary athletes are permitted to compete as the gender with which the athlete identified at the time of registration. However, if an athlete wishes to compete as a gender opposite from the gender associated with the sex assigned at birth, they must adhere to the guidelines for transgender athletes.
"USA Fencing Implements Transgender and Nonbinary Athlete Policy"
The full policy: https://www.usafencing.org/transgender-and-nonbinary-policy