I would not. Your sentence is a conditional and "would" is the normal modal verb. In addition I would change "you" to "I".
Student or Learner
"If Santa really does see everything you do, then I could be in trouble"
Can I replace could with can in this sentence? As could means possibility here, in my opinion, so can also works. Isn't it?
'If Santa really saw everything I did, then I would be in trouble.'
Is this second conditional correct?
Not a teacher.