Resonant light scattering by metallic and high-index dielectric nanoparticles has received enormous attention and found many great applications. However, low-index dielectric nanoparticles typically do not show resonant scattering behaviors due to poor light confinement caused by small index contrast. This Letter describes a simple and effective approach to drastically enhance the resonance effect of the low-index particles by partial metal dressing. Mie resonances of low-index nanoparticles can now be easily visualized by scattered light. This scattering peak depends on sphere size and has a reasonable linewidth. A size difference as small as 8 nm was resolved by a peak shift or even by color change. The scattering peak is attributed to the enhanced Mie resonance of the low-index nanospheres. The metal dress not only provides a high-reflection boundary, but also functions as an antenna to couple the confined light power to the far field, leading to scattering maxima in the spectra. Additionally, the enhanced Mie resonance in low-index nanoparticles features a considerable magnetic response due to the strong circulating displacement currents induced by the intensified field despite of a low permittivity (hence low index) of the particles. The enhanced Mie resonances could be used to sense minute changes in size or refractive index of low-index nanoparticles and benefit a wide range of applications.