I'm not sure if what the question is because you can create a 2 column table.
PdfPTable mainTable = new PdfpTable(2);
mainTable.addCell(<phrase cell>);
mainTable.addCell(<image cell>);
You can also, if that was the question, add a nested table to a single cell in your main table. Something like this (to illustrate):
Phrase phrase = new Phrase(text, font);
cell1 = new PdfPCell( phrase );
Image img = ...
cell2 = new PdfPCell( img );
//Create nested table
PdfPTable dummyTable = new PdfPTable(2);
dummyTable.addCell(cell1);
dummyTable.addCell(cell2);
//Add nestedTable to cell of your main table
PdfPCell myCell = new PdfPCell(dummyTable)
mainTable.addCell(myCell)