To simplify the expression \((10^9)^7\) using the Power Rule of Exponents, we apply the rule which states that when raising a power to a power, we multiply the exponents.
So, we have:
\[ (10^9)^7 = 10^{9 \cdot 7} = 10^{63}. \]
Therefore, the correct response is:
1063 (10 superscript 63 baseline).