under PA estate planning probate laws would medicaid or a nursing home be able to make a claim on inheritance

The technical answer is that she can disclaim the inheritance, but the disclaimer would have the same effect as a gift to the other beneficiaries. As a result of the "gift" she will likely become ineligible for Medicaid for a period of years. More facts would be needed in order to make a decision if a disclaimer is prudent or not.

A discaimer or refusal of an inheritance is generally treated as a gift by most state Medicaid agencies. As such, she would/could be penalized by Medicaid, meaning that she would becoem ineligible for Medicaid to pay for nursing home care for a certain number of months, depending on the size or amount of the inheritance she elected not to receive. A PA elder law attorney can assist you with various asset protection strategies that exist in your state, to protect the assets she currently has while optimizing her benefits or minimizing the effect of the inheritance.