Can a Catholic couple enter into a pre-nuptial agreement. This is a huge discussion recently among marriage planning individuals.
This is a canonical question, so I recommend you consult your diocesan offices. But if by “pre-nuptial agreement” you mean “how we are going to divide possessions in the event of a divorce,” that would probably be grounds for declaring the marriage null. It may show that the couple do not intend to enter a commitment that is permanent. The Catholic Church expects more.