My lease terms say that if the tenant is in default I can change the locks, or skip the pay or vacate notice. Is this enforceable?


No.

No matter what the tenant agreed to in the lease,  a landlord must go through the court process. A landlord may never change the locks, or engage in any similar self-help eviction tactics. It makes no difference what the lease terms are. It makes no difference that the landlord may not be interested in collection efforts, and just wants the property back.

Also, service of a notice to pay rent or vacate or other legal steps in the eviction process cannot be waived by the terms of the lease.