will the SIM card for my iPhone SE generation 1 be compatible if I buy an iPhone generation 2?

Yes. The First generation iPhone SE uses the same size nano sim as the new second generation iPhone SE.

See here: Learn which size SIM card your iPhone or iPad uses - Apple Support

sweetsue0332 wrote:

Will the SIM card for my iPhone SE generation 1 be compatible if I buy an iPhone generation 2?

if it is the small nano sim then yes it is compatible.

I also would appreciate this info. Thanks