Short answer
The biggest difference is the zodiac. Vedic astrology (Jyotish) uses the sidereal zodiac, tied to the stars, while most Western astrology uses the tropical zodiac, tied to the seasons. The two are now about 24°14′ apart, so your Vedic sign is usually one sign behind your Western one. Vedic astrology also leans on the Moon sign, Nakshatras and Dasha periods.
How ChiChakra reads this
ChiChakra follows the Vedic method: sidereal zodiac, Lahiri ayanamsa, mean nodes for Rahu and Ketu, and transits counted from your Moon sign.
Key differences at a glance
Reference point: Western horoscopes are built around the Sun sign; Vedic forecasts start from the Moon sign and the Lagna (Ascendant).
Planets: Vedic astrology uses the nine grahas, including Rahu and Ketu (the lunar nodes), and traditionally leaves out Uranus, Neptune and Pluto, which Western charts use.
Timing: Vedic astrology relies on Dasha periods and Gochara (transits from the Moon); Western astrology uses transits and progressions.
Extra layers: Vedic adds the 27 Nakshatras and divisional charts, while Western astrology puts more weight on aspects between planets.
Good to know
Neither system is 'the real one'. They read from different frames, so compare like with like.