The President of the United States can prevent the appropriations bill from becoming law by vetoing it. The Constitution grants the President the power to veto any legislation passed by Congress, which means the bill would then be returned to Congress for further consideration.
If the bill is vetoed, Congress can attempt to override the veto by a two-thirds vote in both the House of Representatives and the Senate. If successful, the bill would become law despite the President's objections. However, if Congress fails to override the veto, the bill will not become law.
In addition to the President's veto power, individual members of Congress can also try to block the bill by speaking out against it and rallying opposition among their colleagues. They can try to convince their fellow members of Congress to vote against the bill or to make changes to it that would reduce its impact on the national debt.
Another way to prevent the appropriations bill from becoming law is through legal challenges. If the bill is deemed unconstitutional or violates existing laws, individuals or groups may file lawsuits challenging its validity.
It's worth noting that the appropriations bill must be signed by the President to become law, and the debt increase authorized by the bill can only be incurred by the federal government once it has been appropriated and spent. Therefore, it is possible for Congress to pass a bill authorizing a large increase in the national debt without actually causing it to increase if the appropriations are never made.