How to fix oil plug that won't tighten? Think nut welded inside oil pan broken.

The drain plug just spins but doesn't come out, its a steel pan. So far what I've found sounds like the pan needs replaced since it isn't possible to remove without damaging it. Thanks for your answer.

Check eBay for a 'new' oil pan...... Then shop local parts stores for price comparison. No more than it cost, best to replace it anyway!