This goal of this clinical trial is to learn whether the drug combination of intraperitoneal paclitaxel (chemotherapy given directly into the abdominal cavity) and intravenous NALIRIFOX (chemotherapy given into a vein, including fluorouracil, leucovorin, oxaliplatin, and liposomal irinotecan) is safe and works in adults with pancreatic cancer that has spread to the peritoneum. The main questions it aims to answer are: * Are people with pancreatic cancer able to tolerate the combination drug regimen? * How well does the combination drug regimen work to treat pancreatic cancer? Participants will: * Obtain a port that goes into the abdomen to deliver intraperitoneal paclitaxel (called an intraperitoneal catheter) * Receive treatment with intravenous NALIRIFOX once every 2 weeks and intraperitoneal paclitaxel on days 1 and 8 of each 14-day cycle * Visit the clinic with each treatment for checkups and laboratory testing * Have imaging scans and blood lab testing to determine response to treatment * Have abdominal fluid lab testing that may help determine if the cancer is responding to treatment * Fill out questionnaires to see how the treatment affects how participants feel and function * Continue follow up after treatment ends to track survival Some participants may be able to have surgery later if the cancer responds well. This is called conversion surgery. To be eligible for surgery, the cancer must have shrunk or stayed the same, peritoneal fluid (from the abdomen) must no longer show cancer cells, and a tumor marker called CA 19-9 must decrease or return to normal. The decision to do surgery will depend on the treating surgeon. By testing this new treatment strategy, researchers hope to find a safer and more effective way to treat people with pancreatic cancer that has spread to the abdomen. If successful, this approach may lead to longer survival, better quality of life, and more people becoming eligible for surgery.