Eh? Are you suggesting putting a whole ton of protons and neutrons together very closely? What's "RAW NUCLEI"? That's some real nice pseudoscientific jargon.
This does not assure any sort of strength. First, with that many particles together, your sword (other than weighing tons) would go critical and a large nuclear explosion would follow. Second, density does not assure that something is strong. Lead, for instance, is quite dense but very weak. Gold is also soft. Third, assuming your "RAW NUCLEI" are just protons and neutrons, your hypothetical material would be highly reactive as it would be a huge sink for electrons. The material would probably be the most acidic thing in the world.