Klipsch speakers are amazing indeed. I own a sub/satellite set patched thru an Onkyo receiver. Incredibly crisp highs and earth shaking lows.
You would probably use RCA to 1/4" TS cables for a direct cable from the Nautilus L/R outs to the tape/aux inputs on your Sony. Unless your line input is on the front panel with a 1/8" TRS connector.
I keep a box of these types of connectors and adapters handy for convenience.
here are examples.
A lot of stereos these days use line level inputs for MP3 players and such.
your mileage may vary.