Help - I haven't paid any quarterly taxes this year

I've always had sufficient tax withholding to cover my primary job, my side gig, and dividends.  But I retired last year and this year, I've had no tax withholding.  I expect my Taxable Income this year from my side gig and dividends to be about $80K.  Can I catch up?  What should I do right now?  I'm willing to overpay some now to avoid a penalty.