The two hottest areas of research in condensed matter physics are complexity and nanoscale physics. Interestingly, these two areas have little overlap as most of the nanophysics research work is conducted using 'simple' materials of metals or semiconductors instead of complex materials such as transition metal oxides. However, due to the strong electronic correlation, it is exactly the transition metal oxides that will most likely lead to observations of striking new phenomena under spatial confinement. We will use perovskite manganites as model systems to demonstrate how spatial confinement can dramatically affect their transport and magnetic properties. The emerging magnetic and transport behavior is likely associated with the electronic phase separation under confined geometry in the manganites. Some of the new properties such as ultrasharp jumps of magnetoresistance and reentrant metal-insulator transition may have significant impact on fabricating oxides-based novel devices.