Following code would work for you. I tested it with GUIDE. I just created a pushbutton with following callback fuction. The callback would paste the data into the table with tag 'uitable1'.
import = importdata('-pastespecial');
%% Convert Nx1 cell array into NxM cell array. The delimiter in each row is TAB character %ASCII value 9
import1={};
for i=1:length(import(:,1))
TAB_char=regexpi(import{i},char(9));%find tabs
temp={import{i}(1:TAB_char(1))};
for comma_i=2:length(TAB_char)
temp=[temp,{import{i}(TAB_char(comma_i-1):TAB_char(comma_i))}];
end
temp=[temp,{import{i}(TAB_char(end):end)}];
import1=[import1;temp];
end
set(handles.uitable1,'Data',import1);