Here is a list of specifications for the two phones you mentioned:
LG G2
It is a smartphone with some impressive features.
General
1. Physical dimensions of the phone are 138.5 x 70.9 x 8.9 mm that can fit in your palm.
2. A 5.2 inch screen with 1920 x 1080 resolution with Corning Gorilla Glass 2.
3. Pixel density 423.
4. Available in Black and White variants.
Camera
1. 13 MP rear camera for those nice pictures. The camera boasts of OIS -Optical Image Stabilisation and 8X zoom.
2. A 2.1 MP front snapper for the wonderful selfie moments.
Hardware
1. It runs on powerful Qualcomm Snapdragon 800 quadcore processor clocking at 2.26 GHz .
2. 2 GB RAM on the device can handle any kind of heavy use with ease and without lags.
3. 16 GB internal memory .
4. Adreno 330 GPU offers wide range of graphics easily.
Other features
1. The phone runs on Android 4.2.2 Jelly Bean.
2. Upgradable to KtKat 4.4.2.
3. Sensors on the device include Accelerometer, Gyroscope, Proximity sensor and compass.
Battery
1. Non removable 3000 mAh battery.
2. Standby time up to 790 Hours.
3. Talktime under standard conditions 16 and hours for 2G and 3G respectively.
Priced at around Rs.26000, G2 is quite a great for its genre.
LG NEXUS 5
Some of the better features of Nexus 5 include-
General
1. Physical Dimensions of the device are impressive 137.9 x 69.2 x 8.6 mm.
2. 4.95 inch screen with 1920 x 1080 resolution protected with Corning Gorilla Glass 3.
3. The device has 445 PPI pixel density.
4. Color availability- Black, White and Red.
Camera
1. The device carries a 8 MP camera with a resolution of 3264 x 2448.
2. Selfie lovers can rejoice with the 1.3 MP front camera.
Hardware
1. It is powered by Snapdragon 800 quadcore processor clocking 2.3 GHz.
2. Adreo 330 GPU for your graphic immersion.
3. Available in 16 GB and 32 GB variants- no external card support.
4. A 2 GB onboard RAM for smoother and lag free operation.
Other features
1. The phone runs on Android Lollypop 5.0
2. Has a bunch of sensors including barometer, Gyro and proximity sensor.
Battery
1. Comes with a non removable 2300mAh battery.
2. Standby time up to 300 hours.
3. Talktime as claimed by manufacturer is up to 17 hours on 3G.
Priced at around Rs.25000, the phone has a mediocre camera which may be a deterrent for photography enthusiasts.
Conclusion
Since you are interested in comparing the two phones, a comparative analysis would be more useful.
Look and Feel- G2 is soft and rounded while Nexus is hard and angular in looks.
Screen- Pixel density is little high on Nexus. Screen size differs by just 0.25 inches. G2 has Gorilla Glass 2 while Nexus carries 3.
Hardware- Both devices are powered by same processor.
Camera- This is where similarity ends and G2 excels. If a good camera is what matters to you, go for G2.
Battery- G2 again is the winner here with an impressive battery backup.
Live....and Let Live!