Ready made formula is sterile so you should be fine to just wash in hot, soapy water

I am one of those terrible mums that didn't sterilize bottles/teats

I fill my sink with crazy hot water (my tank is set to 140) and let the bottles/teats soak for at least 30 mins with soapy water... then I wash and air dry.
Canada only suggests sterilizing/boiling water if you have questionable water source... that said, I boiled water for formula (I use concentrate) until DD was 5 months old... we do have great city water, but things do happen.