Change the O-ring; overtightening the Nuts just strips threads.

Also People have said said that the various Oil Filter Kits don't all have O-rings that fit well.

More extreme: Remove the Oil Filter Top and degrease it with Brake Cleaner and coat from the O-ring up with a thin layer of Silicon Sealant an re-install it. Do this during the day so there is some possiblilty that the Silicon will Cure after 4 hours or so.
A Hair Dryer/Blower to keep the Oil Fitler Top warm would speed up the cure time.

When I worked in a Fuel Injecting Shop we rebuilt a Fuel Injection Pump for a Man from Alaske. The Gasket Kit came with Nylon Pipe Plugs.

When he got back to Alaska he found that at night the Nylon Plugs seeped Fuel until the Engine was warmed up (It was a Generator Engine inside of a Shed).
Evidently the Nylon shrank in the cold.

A Steel Plug fixed it.

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84 300D, 82 Volvo 244Gl Diesel