This part of the Heparin Sodium leaflet doesn't mention nicotine at all, so it gives no information about taking the two together. The passage is about other medicines. It says that if Multiparin is given with warfarin or dicumarol, blood should be drawn for the clotting test (prothrombin time) only after a gap. That gap is at least 5 hours after the last dose into the vein, or 24 hours after the last dose under the skin. It then lists medicines that affect platelets, such as aspirin, ibuprofen, indomethacin, dipyridamole and hydroxychloroquine. The text is cut off partway through that list. Nicotine isn't named in the passage, so I can't say from this text whether there is an interaction. If you use nicotine (cigarettes, patches or gum) and are on heparin, ask your doctor or pharmacist.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.