"That girl is standing on a chair."
Translation:वह लड़की कुर्सी पर खड़ी है ।
No. Firstly, खड़ी is an adjective so you need to combine it with the verb होना to make it a verb.
'Stands' would be खड़ी होती है
One might think that 'खड़ी हो रही है' would then be 'is standing' but it is not so. It actually means 'is standing up', i.e, 'is in the process of standing up'.