\[1)\ \log_{\frac{1}{16}}\sqrt[5]{64} = \log_{2^{- 4}}\left( 2^{6} \right)^{\frac{1}{5}} =\]
\[= \log_{2^{- 4}}2^{\frac{6}{5}} = \log_{2^{- 4}}\left( 2^{- 4} \right)^{- \frac{6}{20}} =\]
\[= - \frac{6}{20} = - 0,3.\]
\[2)\ \log_{8}{\log_{4}{\log_{2}16}} =\]
\[= \log_{8}{\log_{4}{\log_{2}2^{4}}} = \log_{8}{\log_{4}4} =\]
\[= \log_{8}1 = \log_{8}8^{0} = 0.\]