$modx->runSnippet($snippetName, $params);
Evolution:$modx->runSnippet($snippetName, $params);
http://modxdeveloper.com/blog/the-wrapper-snippet-run-a-snippet-from-within-another-snippet
http://rtfm.modx.com/display/revolution20/modX.runSnippet
http://rtfm.modx.com/display/revolution20/modX.runSnippet