Sales of Apple's ( AAPL) iPod nano were huge this weekend in its debut on the market, Jim Cramer said on his "Mad Money" TV show Monday. That means good things for PortalPlayer ( PLAY), which makes audio chips for the device. Thomas Weisel Partners raised year 2005 sales estimates Monday for the iPod to 10 million units, up from 7 million to 8 million units. That means upside for PortalPlayer, said Cramer. The next big thing on the horizon, Apple's video iPod, also is likely to use PortalPlayer's chips, said Cramer, although some believe the contract will go to Sharp. Should that happen, said Cramer, he would simply ring the register. Cramer said insiders have been selling PortalPlayer's stock but Cramer is not concerned. Insiders "sell for a million reasons," he said, and stock sales by insiders are rarely a reliable indicator of where a stock is headed. Cramer said there is no reason to buy PortalPlayer immediately if you're cautious, as the stock has had a bit of a run. And, if Cramer had bought the stock before its run, he probably would be taking some profits now. However, he believes the stock is still headed higher. In response to a question about disk-drive makers Seagate Technology ( STX) and Komag ( KOMG), Cramer would sell Seagate and doesn't want anything to do with Komag. Commenting on flash-memory plays, Cramer likes Lexar Media ( LEXR) and SanDisk ( SNDK), but don't overlook Silicon Motion Technology ( SIMO), he said.