The　nonlinear　dynamical　equations　are　established　for　the　double　layered　viscoelastic　nanoplates　(DLNP)　subjected　to　in-plane　excitation　based　on　the　nonlocal　theory　and　von　Karman　large　deformation　theory.　The　extended　high　dimensional　homoclinic　Melnikov　method　is　employed　to　study　the　homoclinic　phenomena　and　chaotic　motions　for　the　parametrically　excited　DLNP　system.　The　criteria　for　the　homoclinic　transverse　intersection　for　both　the　asynchronous　and　synchronous　buckling　cases　are　proposed.　Lyapunov　exponents　and　phase　portraits　are　obtained　to　verify　the　Melnikov-type　analysis.　The　influences　of　structural　parameters　on　the　transverse　homoclinic　orbits　and　homoclinic　bifurcation　sets　are　discussed　for　the　two　buckling　cases.　Some　novel　phenomena　are　observed　in　the　investigation.　It　should　be　noticed　that　the　nonlocal　effect　on　the　homoclinic　behaviors　and　chaotic　motions　is　quite　remarkable.　Hence,　the　small　scale　effect　should　be　taken　into　account　for　homoclinic　and　chaotic　analysis　for　nanostructures.　It　is　significant　that　the　nonlocal　effect　on　the　homoclinic　phenomena　for　the　asynchronous　buckling　case　is　quite　different　from　that　for　the　synchronous　buckling　case.　Moreover,　due　to　the　van　der　Walls　interaction　between　the　layers,　the　nonlocal　effect　on　the　homoclinic　behaviors　and　chaotic　motions　for　high　order　mode　is　rather　tiny　under　the　asynchronous　buckling　condition.　(C)　2015　AIP　Publishing　LLC.